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Патент USA US2113163

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/ APl'il'5, 1938.
Filed July 16, 19,55
Luv: fkmuemv
. A’
' J
Patented Apr. 5, 1938
Kurt Schlesinger, Berlin, Germany
Application July 16, 1935, Serial No. 31,712
In Germany July 20,1934
2 Claims.
(Cl. 250-36)
In my application Ser. No. 668,940, ?led May
2, 1933, Patent No. 2,083,202, granted June 8,
For example, 2 in the line portion is 0,01 mi‘.
and in the frame portion 2 mf.
1937, there is described an arrangement for gen
erating relaxation oscillations consisting of a
The present invention sets forth in what man
ner under different conditions of this kind the
5 charging condenser, which is periodically charged
through a charging resistance by a direct cur
rent source and discharged by means of a grid
controlled glow discharge tube.
In these discharge tubes the grid does not act
10 as a control element but as blocking element.
As long as the control grid possesses a corre
sponding negative potential a discharge does not
take place, however high the potential may be
between the anode and the cathode. Immedi
15 ately, however, the discharge—by shifting of the
grid potential-—having once commenced, the
same—irrespective of any variation in the grid
potentiaL-continues as long as a potential exists
between the cathode and the anode.
In television receiving arrangements there is
applied a synchronizing potential to the grid of
the discharge tube. The generator then will pro~
duce relaxation oscillation controlled by the
It has been pointed out in this earlier applica
tion that it is advantageous to insert a resistance
in the discharge circuit of the glow discharge
tube. This resistance has the object of limiting
the intensity of the discharge current, more par
30 ticularly shortly after effected ignition. If this
resistance is not provided, there occurs a more
or less extensive lack of steadiness in'the tele
vision image, which is due to the fact that the
points of ignition and quenching of the glow tube
35 do not remain sufficiently constant and each
discharge is more or less dependent on the course
of the preceding discharge. This state of de
pendence is explained by the fact that the in
ternal resistance of present-day gas ?lled grid
40 controlled glow discharge tubes is comparatively
small, and accordingly even at the commence
ment of the ignition very considerable amounts
of current are taken from the condenser in very
short periods, viz., in a manner which is not
resistance I may conveniently be dimensioned.
It has been found that the time constant 'TZR'C
must always be equal in both circuits. In conse
quence, according to the invention, there is found
in the line circuit a resistance of 500 ohms and
in the image-change circuit a resistance of about 10
3 ohms as optimum.
The absolute length of this time constant
TZR‘C amounts in the stated cases’taken from
practice to approximately 5-10—6,sec. The se~
lection of these particular time constants results 15
from a requirement which is closely associated
with the length of the synchronization signals
and has likewise been described and substan
tiated in an earlier application. The duration
of the total discharge should be equal to or ~20
greater than the duration of the synchronization
signal. This condition ensures that unsteadiness.
of the screen owing to the co-operation of the
relaxation connection with the control signals is
unable to occur.
I claim:
1. A relaxation oscillation arrangement con-,
sisting of a line frequency generator and a frame
frequency generator, each of said generators
comprising a gas ?lled glow discharge device 30v
having a hot cathode, a grid and an anode, a
chargingvcondenser having one of its ‘electrodes
connected to said cathode and its other electrode
connected through a resistance to said anode,
means for charging said condenser, means to 35
bias said grid negatively with respect to said
cathode and. means to apply a synchronizing
voltage to said grid, the time constant of the
system constituted by said resistance and said
charging condenser being in the order of 5-10-6 40
see. for each of said generators.
2. A relaxation oscillation arrangement con
sisting of a line frequency generator and a
frame frequency generator, each of said gen
erators comprising a glow discharge device hav» 45
ing a hot cathode, a grid and an anode, a charg
arrangement of the resistance l, the condenser’ ing condenser having one of its electrodes con
being designated 2, whilst 3 is the gas ?lled grid nected to said cathode and its other electrode
connected through a resistance to said anode,
controlled glow discharge tube of the line fre
quency, l’, 2’, and 3’ indicating corresponding means for charging said condenser, means to 50
bias said grid negatively with respect to said
elements of the frame frequency generator.
cathode and means to apply a synchronizing
It has been found that a resistance l of this voltage to said grid, said charging condenser hav
kind is necessary not only in the line relaxation ing a value of 0,02 mf. for the line frequency
circuit but also in the vertical relaxation circuit, generator and a value of 2 mi. for the frame fre
i. e., the so-called frame circuit. The two relaxa
45 capable of exact control.
In the drawing there is shown the fundamental
quency generator, said resistance having‘a value
tion condensers 2 in these two circuits are, how
ever, very diiferent, their ratio being the same as
the number of lines in the image, i. e., as 1:200.
of 500 ohms for the line frequency and a value of
5 ohms for the frame frequency, generator.
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